Improvement in grooving sheet-metal pipes



UNITED STATES PATENT OFFICE.

CHARLES LETTERMAN, OF SYRACUSE, NEW YORK.

IMPROVEMENT IN GROOVING SHEET METAL PIPES.

Specification forming part of Letters Patent No. 2] 3,214, dated March11, 1879; application filed January 25, 1879.

To all whom it may concern:

Be it known that I, CHARLES LETTERMAN, of Syracuse, in the county ofOnondaga and State of New York, have invented a new and valuableImprovement in Grooving Sheet- Metal Pipes; and I do hereby declare thatthe following is afull, clear, and exact description of the constructionand operation of the same, reference being had to the annexed drawings,making a part of this specification, and to the letters an d figures ofreference marked thereon.

Figure 1 of the drawings is a representation of a side elevation, partlyin section, of my device, and Fig. 2 is a sectional detail view of thesame. i

The nature of my invention consists in the construction and arrangementof an apparatus for grooving the ends of stove-pipes or othersheet-metal pipes to form screw -threads, as will be hereinafter morefully set forth.

In the annexed drawings, A represents the base of the machine, fromwhich rise two vertical standards, B B, connected at their upper ends bya cross-bar, O, forming the frame.

pass through the standards said standards are provided with projectinghubs, as shown at d, to form elongated bearings for the shafts.

Upon the mandrel D, on the outside of the other standard B, is attacheda cylindrical die, G, formed with a coarse exterior screwthread, 0, saiddie being fastened by a setscrew or otherwise, as deemed mostconvenient, so as to be readily removed and another of different sizesubstituted, according to the size of the pipe to be operated upon.

The cross-bar O of the frame is projected over the die G, and isprovided with two downwardly-projecting bars, f f, between which isplaced a slide, H, adjustable up and down by means of a set-screw, I.The slide H is, on its under side, provided with two ears orprojections, h h, in which is fastened a rod or shaft, 1. 7 On this rodis loosely placed a wheel or roller, m, of such size as to correspondwith the thread 6 in the die G.

Upon the projecting end of the mandrel D is placed an adjustable collar,J, fastened at any point by a set-screw or otherwise. This collar issimply intended to hold the pipe in proper position-that is, concentricwith the shaft and die.- The pipe being passed over the collar J, andits inner end fitting over the die G, the slide His pressed down by theset-screw 1 until the roller m indents the pipe by pressing it down inthe thread 0 on the die. By now turning the crank F, the mandrel D anddie G, with the pipe, will be rotated, and the roller 921., being looseon its shaft '6, will follow the thread on the die G, and thus form acoarse 7 thread on the pipe.

Stove-pipes or other pipes being thus formed at their ends with coarsethreads can be easily joined together.

I claim- 1. The combination of a rotating cylindrical die provided withexterior screw-threads, and a roller placed loosely on a rod or shaftparallel with the axis of the die, substantially as and for the purposesherein set forth.

2. The slide H, carrying the rod or shaft 2', with loose roller mthereon, and adjusted by means of a screw, I, in combination with therotating die G, substantially as and for the purposes herein set forth.

In testimony that I claim the above I have hereunto subscribed my namein the presence of two witnesses.

CHARLES LETTERMAN.

Witnesses JOHN BANSINGER, 0am MOGARTY.

